Roll-painting apparatus



p 1954 H. NELSON I 2,689,545 ROLL-PAINTING APPARATUS Filed June 30, 1950 2 Sheets-Sheet 1 VINVENTOR I HARRY mam/v BY wfyw IS ATTORNEYS Sept. 21, 1954 H. NELSON 2,689,545 ROLL-PAINTING APPARATUS Filad June 30, 1950- 2 Sheets-Sheet 2 INVENTOR HARR Y NH SO/V BY fl M r2404.

HIS ATTORNEYS Patented Sept. 21, 1954 ROLL-PAINTIN G APPARATUS Harry Nelson, New York, N. Y., assignor to Lorentzen Hardware Mfg. Corp., New N. Y., a corporation of New York York,

Application June 30, 1950, Serial No. 171,450

10 Claims. 1

This invention relates to a method and apparatus for the roll-painting of thin sheet metal strip.

Sheet metal strip of indeterminate length and uniform width is sometimes passed between a pair of soft rubber rolls continuously coated with paint in order to paint the sides and edges of the strip, after which the strip may be baked or otherwise dried and then recoiled. Among the types of paint which may be applied in this manner are the urea alkyd and vinyl types of synthetic enamels.

In the roll-painting of sheet metal strip stock, it is possible to apply avery even coating of paint to the sides or faces of the strip by a pair of opposed rollers, one located above and one located below the strip and both pressing very lightly on the strip. The paint on the rollers comes around and completely coats the edges of the strip, particularly in the case of a relatively thin strip having a thickness up to .040 to .050 of an inch. In fact, the problem in painting such a strip is not one of applying paint to the edges of the strip but in preventing beads or zones of greatly increased thickness along the edges. Such paint beads are particularly detrimental when the strip is subsequently to be roll-formed into finished shapes; e. g., channel sections used for Venetian blind head bars, bottom bars, and metal fascia boards, since the thickened paint is more likely to scale off so as to leave the bare metal exposed.

The present invention contemplates the introduction of a thin metal blade close to each side of the metal strip during its passage between the paint rolls in order to prevent the formation of a heavy layer of paint along each edge of the strip. In the form shown of the present invention, these blades are incorporated in a fitting supported by the strip and riding on the portion of the strip in advance of the paint rolls.

It is sometimes desirable that a strip that is subsequently to be roll-formed be given a full, opaque coat of paint on one side and a somewhat thinner, translucent coat of paint on the other side in order to facilitate the rolling of the strip and prevent galling of the forming rolls by small metal particles from the strip. In the form shown of the present invention, this is accomplished in part by feeding the strip upwardly to and downwardly from the painting rolls so as to produce a greater pressure of the lower painting roll on the strip since the strip is under tension, and therefore produce a thinner coat of paint on the lower side of the strip. In addition, a scraper may also be provided to remove some of the paint from the lower r011 before it .contacts the strip and further reduce the amount of paint applied to the strip.

It is an object of the present invention to provide an improved method and apparatus for applying a smooth, uniform, opaque coat of paint to one side and the edges of thin, flat, sheet metal strip and a thinner, translucent coat of paint to the other side of the strip.

Another object is to generally improve apparatus and methods for the roll-painting of thin sheet metal strip.

Further objects and objects relating to details and economies of construction and use will more definitely appear in the detailed description to follow.

My invention is clearly defined in the appended claims. In the claims, as well as in the description, parts are at times identified by specific names for clarity and convenience, but such nomenclature is to be understood as having the broadest meaning consistent with the context and with the concept of my invention as distinguished from the pertinent prior art. The best form in which I have contemplated applying my invention is illustrated in the accompanying drawing forming part of this specification, in which: i

Fig. 1 is a diagrammatic, perspective view of the machine of the present invention, showing in broken lines a strip of metal being passed through the machine for painting.

Fig. 2 is an enlarged side elevation of the fitting for preventing the formation of paint beads on the strip during painting, the strip and paint rolls being shown diagrammatically.

Fig. 3 is a top plan view of the fitting shown in Fig. 2, the strip and bottom paint roll being shown diagrammatically.

Venetian blind head bars and bottom bars are often formed of painted metal channels. These channels may be formed from a thin strip of sheet metal of uniform width and thickness and indeterminate length, which is passed through a roll-forming machine to form the desired contour, after which the channel is severed to form sections of predetermined length.

There are certain advantages inherent in painting such a strip before it is given its channel form. A coating of paint of more uniform thickness can be obtained by painting the flat strip rather than the completed channel and, in addition, there is a saving in equipment and labor. Fig.1 shows diagrammatically the paintgreater pressure against the lower roll, and decreases the pressure between the strip and the upper roll I 0. Thus, the thickness of paint on the underside of the strip 26 may be controlled not only by the amount of paint on the lower roll H at the point of contact with the strip but also by the angle at which the strip is fed through the rolls. Whenever the angle at one side of the stri made by the strip entering and leaving the rolls is less than 180, the strip will bear heavier on the roll on that side and produce a thinner coat of paint.

The above-described machine serves to coat the strip 26 with a coating of paint of substantially uniform thickness and avoids producing a thicker film of paint along the edges of the strip. This machine is particularly effective when used with synthetic enamels of the urea alkyd and vinyl types.

I claim:

1. Apparatus for roll-painting thin sheet metal strip of uniform width to produce a uniform coat of paint on one side and the edges and a thinner coat of paint on the other side, said apparatus comprising: a pair of opposed, soft, closely spaced, paint-applying rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, means for supplying paint to the surface of the rolls, means for tensioning the strip in its passage through the rolls and directing the strip so that the angle made by the strip entering and leaving the rolls is less than 180 on one side of the strip, means to scrape most of the paint from the paintapplying roll on that side of the strip, and a pair of thin, blade-like members extending through and beyond the nip of the rolls, one member being located closely beside each edge of the strip.

2. Apparatus for roll-painting thin sheet metal strip of uniform width to produce a uniform coat of paint on one side and the edges and a thinner coat of paint on the other side, said apparatus comprising: a pair of opposed, soft, closelyspaced, paint-applying rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, means for supplying paint to the surface of the rolls, means for tensioning the strip in its passage through the rolls and directing the strip so that the angle made by the strip entering and leaving the rolls is less than 180 on one side of the strip, and a pair of thin, blade-like members extending through and beyond the ni of the rolls, one member being located closely beside each edge of the strip.

3. Apparatus for ro1l-painting thin sheet metal strip of uniform width, said apparatus comprising: a pair of opposed, soft, closely spaced, paintapplying rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, means for supplying paint to the surface of the rolls, and a pair of thin, bladelike members or substantially the same gauge as the strip extending through and beyond the nip of the rolls, one member beside and close to each edge of the strip.

4. Apparatus for roll-painting thin sheet metal strip of uniform width, said apparatus comprising: a pair of opposed, soft, closely spaced, paintapplying rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, means for supplying paint to the surface of the rolls, and a pair of thin, bladelike members extending through and beyond the nip of the rolls and for appreciable distances 6" Y forwardly and rearwardly of said nip, one member beside and having a straight edge closely paralleling each edge of the strip.

5. In a machine for roll-painting thin sheet T metal strip of uniform width, a pair of opposed,

cylindrical, closely spaced, painting rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, and a fitting for preventing the formation of beads of paint along the side edges of the strip during the passage of the strip between the rolls, said fitting comprising a pair of thin blades connected by a central guide sectionriding upon the strip in advance of the painting rolls with the blades extending through and beyond the nip of the rolls, one of said blades being positioned beside and close to each side edge of the strip.

6. In a machine for roll-painting thin sheet metal strip of uniform Width, a pair of opposed, cylindrical, closely spaced, painting rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, and a fitting for preventing the formation of beads of paint along the side edges of the strip during the passage of the strip between the rolls, said fitting comprising a pair of thin blades connected by a central guide section riding upon the strip in advance of the painting rolls with the blades extending through and beyond the nip of the rolls, one of said blades being positioned beside and close to each side edge of the strip, the fitting having means for preventing the guide section thereof from being carried into the rolls.

'7. In a machine for roll-painting thin sheet metal strip of uniform width, a pair of opposed, cylindrical, closely spaced, painting rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, and a fitting for preventing the formation of beads of paint along the side edges of the strip during the passage of the strip between the rolls, said fitting comprising a pair of thin blades extending through and beyond the nip of the rolls beside the strip and supported with one blade slightly spaced from each edge of the strip.

8. In a machine for roll-painting thin sheet metal strip of uniform width, a pair of opposed painting rolls between which the strip is adapted to be passed, the rolls being mounted for rotation on parallel axes, and a fitting for preventing formation of beads of paint along the side edges of the strip during the passage of the strip between the rolls, said fitting comprising a pair of blades of approximately the thickness ofv the metal strip and supported with one blade slightly spaced from each edge of the strip and extending between the nip of the rolls beside the strip.

9. A fitting for preventing the formation of beads of paint along the side edges of thin sheet metal strip during the roll-painting of the strip by passage between a pair of opposed painting rolls, said fitting comprising: a pair of blades having substantially straight confronting edges positioned in parallel spaced relation within a common plane, the distance between said edges of the blades being only slightly greater than the width of the strip to be painted, and an inverted channel-shaped member adapted to ride along the strip to be painted and having bottom and side walls for closely overlying the top and side edges of the strip, the blades being supported by the channel-shaped member in substantially the plane of the inner bottom surface of the member.

10. A fitting for preventing the formation of edge beads of paint along the side edges of thin 7 sheet metal strip during the roll-"painting of the strip by passage. etweenapair of opposed painting rolls, said fitting comprising: a pair of blades having substantially straight confronting edges positioned in parallel spaced relation within a common plane, the distance between said edges of the bladesfbeing only slightly greater than the width of the stri 'to be painted, and an inverted channehshapedmember adapted to ride along the strip to be painted and having bottom and side walls for closely overlying the top surface and side edges of the strip, the blades being supported by the'ch'annel-shaped member in sub stantially the plane of the inner bottom surface of the'membenanda member extending perpen- 8 dicularly of the plane of'the blades for preventing passage of the channel-shaped member between the rolls.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,476,988 Latta Dec. 11, 1923 1,558,271 Newell Oct. 20, 1925 2,089,524 Abrams Aug. 10, 1937 2,102,679 Carlson Dec. 21, 1937 2,176,981 Smith Oct. 24, 1939 2,492,843 Carman Dec. 27, 1949 

